The key to achieving this is a frame that uses carefully shaped tubes to allow the air to pass over them more easily. This can be done in a variety of ways from simply giving the tubes a teardrop profile or, in the case of the more advanced models, manipulating the airflow over high-drag areas in such a way so as to create a net reduction in drag for the bike as a whole.
An aero frame is not enough however; your wheels, helmet, clothing and, most importantly of all, you need to be optimised for an investment in an aero bike to really pay dividends
Most aero road bikes look fat from the side, but slim from the front.
Aero bikes started to appear after some bright spark wondered if it might be possible to combine the efficiency of a time trial bike with the handling of a road bike. It turned out it was, although early examples of aero bikes were compromised in terms of their stiffness and steering. A lot of subsequent refinement has since improved those characteristics, but it’s taken an awful lot of development work. All of which costs the manufacturers money which needs to be recouped, hence aero bikes are often at the more expensive end of the price spectrum. (There’s also the ‘this is what the pros use’ aspect that adds a premium.)
Price is one thing that might dissuade you from investing in one, but if you ride for fun and fitness rather than racing there are other things that might put you off.
For a start, the extra material required to create those fancy tube shapes often means aero bikes have a slight weight penalty over bikes with slimmer tubes. As such they’re not necessarily the best machines to take into the mountains. Then there’s all the faff that comes with internal cable routing, integrated brakes and increasingly integrated bars, stems and seatposts, which means aero bikes often cause headaches when it comes to adjusting and maintaining them.
There’s no denying that aero bikes offer you an advantage in terms of efficiency, but only a small one. On its own it won’t transform your performance. The advantage falls into the category of marginal gains and they’re called that for a reason: they’re little and they need to be accumulated across your entire riding experience before they make a significant difference.
An aero frame is not enough however; your wheels, helmet, clothing and, most importantly of all, you — since your body accounts for around 80 percent of the drag you generate — need to be optimised for an investment in an aero bike to really pay dividends.
Specialized S-Works Venge ViAS
5.0 out of 5 star rating
With all cables and wires hidden inside, the bike is noticeably quietJames Huang / Immediate Media
Nimble handling and almost telepathic acceleration
For the launch of the ViAS, Specialized invited a few media types to its California headquarters for a day in the company’s “Wind Tunnel”, followed by a day of highly measured F1-level McLaren modelling validation testing, and then a big day of charging around the serpentine mountain roads of Santa Cruz. You can read more about the results of the testing and how the ViAS performed versus a Tarmac in our Specialized S-Works Venge ViAS first ride review —but to give the ending away: Yes, the Venge ViAS is faster. Much faster.
The Specialized Venge ViAS is quantifiably faster than a standard road bike by a wide margin. What’s more, the bike handles like an excellent race bike should, with nimble handling, a highly efficient chassis and supple tyres mounted on deep, wide rims that deliver huge amounts of confidence in fast turns.
While printed 22 and 24mm, the front and rear tyres plump up to 24 and 26mm respectively on the wide-stance CLX 64 rims. Good, supple rubber with a wide footprint means confidence for days in fast corners. And the wheels, for as deep as they are with 525g rims, accelerate surprisingly easily. Once up to speed — forget about it. They are sails.
The S-Works carbon cranks are graced with a Quarq power meter spider and the Shimano Dura-Ace Di2 9070 group is excellent, of course. The S-Works Power saddle is a matter of personal preference.
Fit is always important on any bike, but especially so on the ViAS. Were you to demo a standard bike, the shop could easily swap stem lengths and adjust the height with spacers to get you dialled in and were you to buy this bicycle, I would strongly recommend that you only do so when you are confident in your fit and your professional fitter.
Earlier this month Specialized recalled about 1,000 Venge ViAS frames sold as complete bikes at the S-Works and Pro level along with S-Works modules due to concerns that the rear wheel can come out of the dropouts, which can cause fractures in the rear triangle and cause a rider to lose control and fall. If you want to read more about this recall see our Specialized recalls Venge ViAS rim-brake bikes story.
Cuts fast through the wind but without beating you up along the way
Still impressively light
Aero road bikes might slice through the air with relative ease, but as a category they’re not exactly known to be comfortable or light. The new Trek Madone 9 Series should go a long way toward dispelling that reputation with a super sleek and comparatively feathery chassis that’s not only fast but freakishly cushy on rough roads, too.
The Madone isn’t just comfortable “for an aero road bike” but comfortable, period — no caveats required. Despite appearances to the contrary, the deep-section carbon frame ably damps road buzz but also rounds off bigger and harsher bumps in a way usually only expected of more traditionally shaped bikes. Credit goes entirely to Trek’s awesome IsoSpeed ‘decoupler’ — a mechanical pivot at the seat tube-top tube intersection — and the Madone’s clever dual, nested seat tube design that, in combination, allows for much more flex at the saddle than you’d otherwise get out of a more traditional frame.
The Madone seems to have free speed in spades, too. We haven’t had a chance to verify Trek’s drag claims — specifically ones comparing it to its major competition — but repeated runs on the fast-and-flat test loops surrounding BikeRadar’s US offices in Boulder, Colorado have certainly returned consistently lower times relative to non-aero machines. As expected for this segment, the chassis is plenty stiff, too.
The Madone’s proprietary center-pull rim brakes are not only cleanly integrated into the frame and fork for aero purposes but they also work well — a good thing since there are no other options
The Aeroad is a futuristic-looking bike, sharing many design cues with its time-trial stable mate the Speedmax. Virtually every part of the frameset seems to sport an aerodynamic cross-section, with truncated airfoils throughout, and the way the different frame elements blend together is nothing short of lovely.
The seatpost is aero too and the one-piece H11 carbon cockpit is a thing of beauty that’s claimed to save 5.5 Watts at 45km/h over a standard bar. In short, the Aeroad is one of the slickest yet straightforward designs we’ve seen.
While the calipers are direct-mount units rather than single-bolters, they’re mounted in the usual places rather than being tucked out of sight, making for easier adjustments and minimal hassle when swapping wheels.
SRAM’s wireless-shifting eTap groupset is fantastic. It works very well and the click from the paddles means you always know when you’ve shifted. The Zipp 404 Firecrest carbon clinchers on our test bike are two versions out of date, but still a tasty set of wheels that behave well in crosswind despite their depth.
Great bar shape helps you hold a low-profile position
Zipp wheels with Continental tyres make a great pairing
Launched for the 2015 Tour de France, the new Foil is a complete rethinking of the bike. Key to the bike’s ride, handling and airflow is its beefy, dropped down tube, as its lower position closes the gap between the down tube and front wheel. It also creates a stout, smooth head tube and a large connection with the oversize bottom bracket shell.
Get it out on the road and the Foil’s compact dimensions help it to take off like a scalded cat, and it just keeps going from there. Once you’re up to speed, maintaining your velocity feels the most natural thing in the world. Getting low is made easier as the bar is surprisingly ergonomic and its depth makes it more useful than some similar options.
Helping the Foil spin up to speed are Zipp’s 60 clinchers — the renamed version of its pre-Firecrest profile 404 wheelset. They have a toroidal carbon fairings but alloy rim beds and brake tracks, which adds a few grams but isn’t a hindrance given the all-round performance benefit. They’re great to ride and reassuringly stable at 24mm wide. Best of all they stop effectively in all conditions, and having 25mm Continental tyres is the icing on a very tasty cake.
Fast-paced is precisely what De Rosa is aiming at with its new SK Pininfarina. This abbreviates the Super King name and shares the limelight with the Pininfarina design house (think Ferrari, Alfa Romeo…).
The carbon frameset mixes swoopy curves with straight lines and familiar aero features such as lowered seatstays, a fairing for the rear wheel, an hourglass-shaped head-tube and Kamm-tail profiles for all the forward-facing tubes.
A road aero frame, integrated cockpit and 80mm-deep Vision Metron rims mean a fast but unforgiving ride, right? Wrong. Somehow the SK is as smooth as Teflon-coated silk with a feel that’s similar to a high-quality endurance bike but with the raw speed to embarrass TT machines.
And all of this is paired with Campagnolo’s precise-shifting Super Record groupset. The SK could be our perfect aero bike — engaging, awesome-looking, fast everywhere but with no comfort compromises.
Integrated aero brakes that provide powerful and consistent speed control
Precise handling with rich road feedback
Neat internal cable routing and dedicated battery compartment for electronic groupsets
BMC’s premium aero road frame is uncompromising in its quest for speed. The custom front brakes are integrated into the front of the fork legs at the base of an extended cover that shrouds the head tube. The rear brake is also ‘hidden’ under the big rectangular chainstays to reduce drag.
Despite all the tight-clearance aero styling there’s enough space for 25mm tyres, although you’ll have to juggle/remove brake washers and potentially even shave the pads down to get the widest aero wheels between the brakes though. The Di2 gear cables are routed internally via bolted panels while the battery is tucked away in the profiled seatpost, which also has a triple position saddle clamp for steeper tri-style angles.
The Zipp 60 wheels are OK if not outstanding in terms of aerodynamics but their alloy braking surface is particularly welcome for its consistent all-weather braking too. BMC has also specced the TMR with a 53-39t crankset for maximum speed, though there is some steep climb salvation in the 11-28t rear block. 3T provides the stem and bar while Fizik provides the saddle.
All of this combines to produce a bike that delivers precise handling and rich road feedback — its outstanding brakes and stable aerodynamics make it an absolute demon on descents.
An aero-optimised machine with all-day ride comfort
Broad 25mm tyres add to the frame’s bump-absorbing ability
The Madone 9.2 doesn’t get Trek’s aggressive H1 geometry or the top-grade OCLV carbon, but it does have the American company’s IsoSpeed decoupler — a mechanical pivot at the top-tube seat tube junction that allows it to flex and absorb road vibrations. And it’s remarkable how it enables this aero-optimised bike to take the edge off of big hits. It’s not just a comfortable aero bike, it’s a comfortable bike, period.
The comfortable ride quality is also due in part to the Bontrager R3 Hard-Case Lite rubber. The tyres’ 25mm casing is supple, rolls well and proved surprisingly puncture resistant during the test period.
In its 9.2 guise. the Madone comes with a full Ultegra groupset matched to integrated carbon bars and stem, a carbon aero seatpost and deep-section wheels, all of which come from Trek.
Given the Madone’s aero prowess, the compact 50/34 chainset was something of a surprise, but combined with an 11-28t cassette there’s plenty of low-end gearing to get you up even the steepest gradients. One word of warning, however: the internally routed cables and integrated centre-pull brakes are sure to cause headaches for home and shop mechanics alike.
Adjustable front end adds height without the need for spacers
A purposefully firm ride
Argon 18’s Nitrogen Pro has almost every aero base covered but still manages to introduce some twists, the most obvious being the Aero 3D system to alter the head tube’s height. Instead of spacers, you get a selection of profiled extenders that screw into the head tube to raise the front end without compromising its rigidity.
On the road the Nitrogen Pro behaves just like a pro-level aero road bike. Its planted feel begins with the 24mm-wide, 40mm-deep Racing Quattro Carbon wheelset, with supple Vittoria tyres. The Quattros combine rampant acceleration with stability, all-weather agility and great braking in the dry.
An Ultegra Di2 groupset delivers the usual reliable and slick shifting, and although a compact crankset might not be ideal for high-end performance, it does allow for easier climbing.
While the ride is firm, it’s not ball-bustingly hard. It’s firm with a sense of purpose — which is exactly what you’d expect from a Tour machine.
On its own, the Storck Aerfast frame weighs 990g but is packed with good-looking and practical features, including a faired-in fork crown, bridgeless teardrop seatstays, alloy dropout inserts and ample spacing for wider tyres.
The Aerfast has a surprising amount of front-end flex, which took a while to get used to. There are no spacers beneath the alloy stem to allow flex; rather it’s the result of the vibration-absorbing RBC180 carbon bar, and as the miles ticked by it definitely heightened the feeling of ride smoothness. It didn’t take long to realise that the Aerfast is unlike most other aero bikes — it’s incredibly lively with plenty of positive feedback.
As well as providing great power transfer, the rear end is supple enough to prevent bumps from reaching your backside. It’s assured through the corners and going uphill the Aerfast is a match for the best climbing machines thanks to its low mass and racy wheelset.
The Aerfast is a brilliant ride: it’s urgent, light and agile, with the sort of comfort that some endurance bikes can only dream of. If you’re looking for something different that’ll produce epic speed and look after you all day long, this might be the bike for you.
Rock-solid frame that still manages to blunt the worst of the bumps
The SL in the name stands for ‘super light’, and refers to Lapierre’s claim to have trimmed 20g from the Aircode’s fork and reduced the frame’s weight by 20 percent, while having maintained the same rigidity and ride quality.
The rest of the Aircode is an impressive package for the price — you get a full Shimano Ultegra groupset, Zipp bars and stem, Fizik’s Arione saddle and Mavic’s Cosmic Elite wheels.
As for the ride, the Aircode is as fast as its looks are sharp, and the frame is rock solid through the head tube and down through the bottom bracket.
When the roads start to twist and turn the Aircode is poised, swift and ready to change direction, and holds its line through fast bends with ease. There’s a relative lack of chatter and buzz from the rear end, too, which is a pleasant surprise given how firm the bike feels. That said, you’ll be glad it’s been specced with 25mm rubber and carbon seatpost.
Giant’s Propel has striking looking to go along with its scorching sprint and easy cruising speed.
Its fronted by an aero fork with custom TRP mini V-brakes on the trailing edges that provide plenty of controllable power, but also have two cable anchoring sockets that let you flick between narrow training wheels and full-fat aero in seconds. The Propel is an impressively light chassis too given its stout Overdrive 2 steerer tube and stem, massive bottom bracket shell and big chainstays.
Additional weight saving comes from Giant’s own aero wheels, though their braking and high-speed handling caused some concerns in the big hills, while a Fizik saddle and Ultegra Di2 add to an already impressive package.
While it’ll tap along at tempo or up steady climbs without grumbling, every pedal turn is transmitted directly to the tarmac. That makes it almost impossible not to keep pushing a little harder — it’s as if the bike has an inexhaustible eagerness to accelerate.
Clearance for 25mm tyres in the smoothly sculpted frame
The AiR frame is as smoothly sculpted and aerodynamic as you’d expect from a bike associated with Chris Boardman, Britain’s original hour-record hero. A flush-fit clamp for the aero seatpost and internal cable routing helps keep the airflow clean, as does the rear brake’s position under the big, tapering, rectangular chainstays.
Shimano Ultegra Di2 needs no introduction, but in this instance it comes with an 11-25t cassette for smooth cadence and 50/34t compact chainset for a little help on the climbs. Carbon aero wheels are easy to accelerate and once you’re up to speed the bike sustains it with a quietly efficient determination.
The tapered head tube and relatively tall frame tubes never feel punishing. Even after 12hrs in the saddle we still felt fresh and hands, shoulders, back and backside were a lot more comfortable than expected. There’s plenty of room for 25mm tyres if you want a bit more float too, making this a versatile, high-velocity all-rounder at a keen price.
It’s worth adding that there’s a new version of this bike out for 2017, which keeps the Shimano Ultegra Di2 groupset but runs on a 50/36t crankset, swaps the Fizik saddle for a Prologo Nago Evo 141, and runs on Boardman Air Elite Seven wheels, shod with 25mm Vittoria Open Corsa CX rubber. Price is a much keener £2,999. We’ll update with thoughts on this bike once we’ve ridden it.
With the CWX8800, German online retailer Rose has created an eye-catching machine that combines sculpted aero tubes with disc brakes.
Its carbon frame has a claimed weight of just 990g and although the fork is skinny in comparison, it features aero profiles right down to the thru-axle fittings. The geometry is aggressive, with the frame’s steep head- and seat-tube angles further emphasised by the downward slope of the 17° Profile Aeria stem. It forms a fine cockpit paired with Profile’s carbon Canta bar, but the bolts on its ‘Lip-Lock Clamp’ faceplate are a faff to access — partly due to their position and partly because all the cables pass directly in front of them.
The Rose holds its speed beautifully and on rolling terrain you can happily hammer along. Its smooth front end ensures you remain comfortable, while the steep seat angle puts you directly over the cranks for efficient pedalling.
SRAM’s Red 22 HRD groupset provides shifting that’s smooth and accurate, and its disc brakes are truly impressive — with 160mm rotors (rather than the more typical 140mm ones found on road bikes), more progressive feel and less noise. DT Swiss carbon wheels with 38mm-deep rims are an equally classy choice and they’re shod with Continental’s quick and hard-wearing GP4000s II tyres.